1. Field of the Invention
This invention relates to an apparatus for mixing bone cement in vacuum, in which mixing takes place in a container from which ready-mixed bone cement is ejected by means of a piston in the mixing container for supplying the bone cement to a hollow in the bone wherein a prosthesis is to be fixed by means of the bone cement, the mixing container being connectable to a vacuum device adapted to generate vacuum in the mixing container during mixing.
2. Related Art
For the generation of vacuum in the space on that side of the mixing container piston which contains bone cement, the mixing container is provided with a cover through which said space is connected to a vacuum device. To avoid unintentional shifting of the piston and resulting compression of the components in the mixing container, by vacuum prevaling on one side of the piston, it has been necessary to manufacture for the mixing container a special base which comprises a coupling for connecting the vacuum device to the space of the mixing container on the opposite side of the piston to create the same pressure below atmospheric on said side as in the space of the mixing container where said components are contained. This implies that the mixing container must be connected at two points to the vacuum device, and furthermore it is difficult to retain the mixing container in sealing position on the base.